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assess? 7 lrcgularsurfsceismeant asurface which-'is not substantiallyinaslngleplane, andwhlchincon- Junction with a simple quarter wave stub antenna would not. at the frequency of operation, produce an essentially single-lobe eld pattern. Thus. the term lrresular surface would include Itis apparent that the present invention ma! beembodiedinawidenumberofphysicalforms. eachahpiedtopsrfonnbestitsparticularfimc- :onsunderthcparticular conditionsofuse. It is apparent furthermore that the invention is tcbelimitedtotheproduconofsymmetriiisldpattcrmasitisobviousthatbysuitable mcdiilcationsoftbefiareandcavitystructures desirable patterns may be obl. A forwardly-directed faired-in antenna systemforuseinaimraftnavingmetalwing surfaces comprising an aircraft wing having an electrically-conductive surface, the surface of the leadingedgeofeaidwingdeiiningasharplycurved air foil, an electromagnetic aperture type radiation structure recessed in the leading edgeofsaidwingforradiatingradiowavesina generally forward direction. and forwardlyextending outwardly-flared auxiliary conducting nirfaces interposed between said radiation structure and said sharply-curved air foil and electrically connected along their forwardmost edges to said air foil and along their rearward edges to said radiation structure, said conductive surfaces being positioned to form an abrupt angular discontinuity between said conductive surfaces and said air foil at the junction therebetween, therebytooiferahighimpedancestthefreuuency of operation to the transverse flow of electromagnetic currents therebetween. whereby secondary radiation from the curved wing surfaces is minimised and a desirable lingle-lobe 1fleldpatternisproduced.

. LA forwardly-directed faired-in antenna systemforuseinaircrafthavingmetalwing surfscescomprisinganaircraftwinghavingan electrically-conductive curved air foil surface. an ticspemretyperadistionstructure recessedintheleadingedgeofsaidwingfor radiating radio waves in a generally forward direction,saldstructurehavingarearwalland :forwardly extending walls electrically connected tosaidmarwamtbeforwardedgcsof-saidwalls denning aV radiation aperture, auxiliary conducting surfaces electrically connected to and interposedbetweensaidairfoilandsaidaperturedclining edges of said walls, said auxiliary surfaces being positioned to form an abrupt angular dis-` 'vcontinuity between said auxiliary surfaces and said air foil at the junction therebetween, and an excitation element positioned in said radiation structure and back of said radiation aperture.

saidradiationaperturebeingpositionedasub-- stantial 'Wall and forwardly-extending side walk elecla'lcallyconnectedtosaidrearwalLandoutwardly-fiared forwardly-extending auxiliary amducting surfaces electrically connected to nid side walls and extending forwardly and outwardly therefrom, the forward edles of said auxiliary surfacesbeingconnectedtoandformingan abrupt angular discontinuity with said irregular surface, the lines of juncture of said auxiliary surfaces and said lrresular surface being entirely outside the limits of and forwardly of the forwardmost portions of said side walls.

4. Aforwardly-directed faired-in antcnnasystem for use in aircraft having metal wing surfacm comprising an aircraft wing having an electrically-conductive surface, an electromagnetic aperture type radiation structure recessed in the leading edge of said wing for radiating radio waves in a generally forward direction. said structure havingarcarwallandforwardlyextendingwalb electricallyconnectedtosaidrearwalLtbeforwardedgesofsaidwallsdedningaradiation aperture, and auxiliary conducting surfaces electrically connected to and interposed between said air foil and the forward edges of said apertura denning edges of said radiation structure, said conductive surfaces being substantially planar and positioned to form an abrupt angular dhcontinuity between said conductive surfaces and said air foil at the junction therebetween.

5. A faired-in antenna system for use in arregular surfaces comprising a supporting structure having an irregular. exposed, electricallyconductive surface. an open-faced box havim conductive rear and side walls and an excitation element mounted within said box. cavity type antenna structure including said box being recessed in said supporting structure. and at least one substantially planar, outwardly-flared. auxiliary conducting surface electrically connected to one of said side walls and extending forwardly and outwardly therefrom. said auxiliary surface being connected to said irregular surface along a line of iuncture positioned forwardly of the forwardmost portion of said box.

6. Anaperturetypeantennasystemforthedfrectional radiation and reception of electromagnetic energy over a wide range of frecuencia comprising an irregular electrically conductive surface,acavitystructurerecessedinsaidirregu larsurfaceandhavinganopenfaceonitsforward side. a radiating element positioned within said cavity structure. a transmission system for coupling electromagnetic energy to said element. and auxiliary electrically-conductive surfac. connected to opposite sides of said cavity structure, at leastoneofsaidsurfaces formingasloping wall extending outwardly and forwardly from said cavity structure and being connected along -its forewardmost edge to said conductive surface snddeiiningtherewithalongthelineofiuncturs exposed angles on the forward side substantially greater than degrees and significantly l.

'than 270 degrees.

7. An aperture type antenna system for direcand including first and second forwardly-extending electrically-conductive walls. said first wall including an outwardly-daring portion connect- `ed along its forwardmost edge to said conductive surface, each point along the line of juncture between said first wall and said conductive surface forming the vertex of an exposed angle donned by said conductive surface and the forward sur- 

